Noise silencing type bar actuating arrangement for typewriters



Dec. 20, 1938. j H. BENZING 4 NOISE SILENCING-TYPE BAR ACTUATING ARRANGEMENT FOR TYPEWRITERS Filed July 14', 1956 2 Sheets-Sheet 1 "III INVENTOR Hugo Banging 1 l IORNEYS Dec. 20, 1938. H BENZlNG 2,141,028

NOISE SILENCING TYPE BAR ACTUATING ARRANGEMENT FOR TYPEWRITERS Filed Julyl4, 1936 2 sheets-shed 2 INVENTOR Jfzgo Bengt?? BY v ATTORN Patented Dec. 20, 1938 UNITED STATES NOISE SILENCING TYPE BAR AGIUATING ARRANGEMENT FOR TYPEWRITERS Hugo Benzing, Dresden, Germany, asslgnor to Aktiengesellschaft Dresden, Germany Applicatio vorm. Seidel & Naumann,

n July 14, 1936, Serial No. 90,497 In Germany July 15, 1935 6 Claims. (or. 191-227) A great number of various devices for obtaining a silent operation of the type bars of typewriters have hitherto been tried. One way in which it was tried to obtain silent working was to pad all the parts of the typewriter which strike against one another with noise damping material. But even this expedient was not entirely successful, because even if such padding is resorted to, there still exists a hammer action at the padded places, and such machines, although making much less noise than an ordinary typewriter, are by no means silent. a

This defect is eliminated according to the invention by providing means to eliminate the ham- 15. mer-like blows of one part on another, especially that of the type bar. By these means the clicking noise arising from the operation of the movable parts is eliminated.

But even if this noise has been abated, there still remains the noise due to the blow-like impact of the type bar on the roller. It has hitherto only been possible to eliminate this noise by means of the known typing technique, where a knee joint or link arrangement was interpolated between the key lever and the type bar, which moved the type bar into a "prepared position" in front of the roller and close thereto and without any blow.

This known knee lever arrangement has however the defect, that the links very soon get worn down and that the type then knocks hard and noisily on the roller, and this defect is further intensified by the fact that the types at the sides of the machine are pressed obliquely against the roller by the said knee lever, and this very often leads to bad reproduction of the type. Moreover, all machines having the said knee lever arrangement, if they are rendered more or less noiseless, are rendered so by reducing the writing speed, and the whole machine becomes heavy and clumsy. It isintended according to the present invention to diminish the noise made by the impact of the type on the roller to such a degree that the damping of the noise is at least as good as can be attained with knee lever arrangements, and that at the same time the advantage is gained that the reproduction can easily be adjusted so that it corresponds to the output desired without decreasing the speed-or deleteriously affecting the neatness of the reproduction.

This desirable result is achieved by the fact that the positively guided key actuating arrangement is stopped without shock or blow when inits position of preparedness, whereupon the-type bar or lever completes by itself against all resilient parts which remain in constant contact with it, the reproduction. The resilient parts or springs are so adjusted that they completely, or nearly so absorb the energy of reproduction of the type bars moving towards the roller. Thus the blow of reproduction of the type lever head is kept down to the very minimum, and this can be further enhanced by making it possible to alter the travel which the type lever passes through due to the energy impartedto it in order to diminish the blow-like action of the type-bars more or less. In this case it is however important that the type bar shall not when it reaches the roller be stopped by rigid abutments or stops because that would cause heavy noises. v The appended drawings illustrate several constructional forms of type bar actuating arrangements suitable for carrying the invention into effect:

Figures 1 and 2 show an amplification of the 'type bar actuating arrangement with positive guiding of the key lever parts by means of an elastic organ interpolated between the key levers and the type bars, and a device for stopping the key levers.

Figure 3 shows a modification of the elastic organ.

Figure 4 is a further modification thereof, and

Figures 5 and 6 show a modified type bar actuating arrangement more especially adapted for small typewriters, and working according to the principle of the present invention.

Figure 7 is a detail view of the intermediate lever.

Each type bar or lever l is actuated by means of a pull-link 2a through an intermediate lever 3a, which is pivoted at 4 in the comb 5. The intermediate lever 3a. is actuated by the key lever 6 by means of the rocking lever 'l which is pivoted at one extremity to a projection 8 on the key lever B. A pull link It is pivoted to the free extremity 9 of the rocking lever 1; the other extremity of the said link is pivoted at l I to the intermediate lever- 3a. The rocking lever I has a rolling surface I2 which allows the rocking lever 3a in the first instance to swing around a stationary point l3, thereby putting the intermediate lever-easily and rapidly in motion. In its further course the rolling surface I2 is of such a shape that the rocking lever I imparts an increasing velocity to the type bar-or lever i. The curved rolling surface l2 rolls on a straight fiat rail H which is arranged somewhat obliquely and which extends over the whole width of the machine. For the lateral guiding of the free extremities of the rocking levers a guide comb i5 is provided. The key levers 8 are also guided by a comb l6, and their rest position is limited by a stop H. The key levers 8 are mounted on a spindle I8 in the comb l9, and are acted upon by springs 20, which endeavour to maintain the key levers in the rest positions. The intermediate levers 3a. are also acted upon by links Zia and springs 22a which make up the connection with a step-by-step mechanism, not shown.

When a key lever is depressed the type bar 8 may have such an acceleration imparted to it, that its velocity no longer agrees with that of the respective key lever B, and as in the starting position, the rocking lever i and the link In form an angle it is possible, if the velocity of the type lever l is too great, for the link in to lift the rocking lever 1! oh the rail I4. The same thing may happen, when the key lever returns to its rest position before. the type has printed. In both cases, which may happen simultaneously or may overlap, the rocking lever l strikes the rail ll with a rattling noise as it reaches its rest position, thereby increasing the total amount of the noise of the machine by a few decibels.

This lifting ofi of the rocking lever is to be eliminated according to the present invention, and this is attained by the fact that the rocking levers are positively guided in such a manner that this defect does no longer occur. In order to attain this the intermediate lever 3a.may for instance be provided with an arm 23 reaching downwards over the spindle 4, a pin 25 being mounted on the bent extremity 24 of the arm 28. This pin 25 comes to lie against a curved surface 26, which is provided on a projection 21 of the key leverB. The curved surface 26 is of such a shape that the pin 25 lies in any position the key lever 3 may assume on the surface 26, and has the tendency only to allow a positive rocking motion of the intermediate lever 3a. Thereby the rocking levers l and the link M are positively guided in sucha manner that the rocking lever 1 is in constant contact with the rail l4.

Consequently in no position of the whole type lever actuating arrangement can a lifting oil of.

the sliding and rolling surfaces take place, thus eliminating all clattering noises.

The curved surface 26 is so shaped that it accurately fits the relative motions of the pin 25 in relation to the key lever extension 21, said motion being caused by the rocking lever curve [2, whereby the key lever B, the rocking lever I, the pull bar or link in and the intermediate lever 3a together with the arm 23 respectively form an articulated and positively closed unit in which no play that could cause a clattering noise can arise.

The arrangement as described up to here allows of an almost noiseless forward and backward movement of the key lever system.

The limitation of the lowest desired position of the keys can in this case be effected by a stop 28, which is adjustable on the projection 21 of the key lever by means of a screw 29. This limit stop is preferably given the form of an eccentric or the like, so that its circumferential edge can be used by rocking it around the screw, for the alteration of the deflection of the pin 25.

This stop 28 may now be made use of in order to carry the basic idea of a new typing technique into eifect;

This basic idea consists therein, that the key rods are somewhat before the striking point of the type bar on the roller is reached, stopped, so that the type lever can continue its travel by reason of the kinetic energy imparted to it, and thus finishes the reproduction of the type.

As this reproduction would be effected in the nature of a blow, its motion must be braked, and

i this braking action must be effected by means of some resilient organ which is so designed that it is adapted to completely or nearly completely absorb the kinetic energy of the rapidly moving type lever until it strikes on the roller. It is in any case endeavoured to attain the result that only so much energy shall remain as is absolutely necessary to produce a good reproduction.

According to Figures 1 and 2, respectively, this possibility of an actuation of the type bar as independent from the'movement of the key lever is attained by the fact that an auxiliary lever 3| is pivoted at 30 to the lever 3a. The movement of the lever 3| in respect of the lever 3a is limited by means of a pin 32 mounted on the lever 3a, said pin protruding through an opening 33 provided on the lever 3|, the said opening being oversized in comparison to the pin 32 and preferably lined with a sound dampening material so that it is at all times impossible for metal to strike on metal. The lever 3| is further provided with a nose 34 which lies up against a spring 35 under tension, which in its turn is fixed to the pin 36 of the lever 3a; The lever 3| is connected through the link 2a with the type lever I. The pull links 2; and the springs 22a for the movement of the universal rail, not shown, are however also pivoted to the lever 3a, so that as the key system is stopped the movement of the universal rail and of all its component parts must be ended.

If the key lever 6 is depressed from the position shown in Figure 1 into the position shown in Figure 2, the pin of the lever 3a, 23 and 24 and the stop 28 on the key 6 move in approximately the same direction but at different speeds. The pin 25 has the tendency to follow up the stop 28. By reason of this movement the pin 25 meets the stop 28 slowly and softly, and the stoppage of the key lever system by reason of the meeting of the pin 25 and the stop 28 is efiected without a blow or shock.

If the position shown in Figure 2 has been reached, then the type lever has not yet reached the typing roller. This type lever however keeps on in its travel by reason of its kinetic energy, and the lever 3| together with the nose 34 is pressed against the spring 33 by the link 2a, thus tensioning the said spring. This spring is so chosen that it can absorb, until the type lever I hits the roller, nearly all the kinetic energy of the said type bar, that is to say to use it up; the power of the spring is so calculated that only such an amount of kinetic energy remains in the type bar to be so calculated that it can, beside exerting its usual function as a spring, also exert the required braking effect to brake the type bar moving independently from the key bar system, which is according to Figure l exerted by the spring 35.

In cases where the type bars or levers are of a particularly heavy type, it may occur that neither the spring 35 nor the spring 22a are by themselves sufliciently strong to achieve the reprojection 63' follows up it strikes the lever 46' the noise oi! the impact, is

quired braking springs 35 and neously to effect 22a. are made use of simultathe braking of the type bar in the manner intended, as this is shown in Figure 4.

In the case ofv small or portable typewriters or in the case of machines with keys guided by guide members the principle of the typing technique above described can be carried into effect in the same manner, it the whole of the type bar actuating arrangement is designed in the manner shown in Figures 5 and 6. 1

The type bars 4| are mounted in the segment 42, which is not subjected to any knocking shock, and they effect the roller 43. The type bars are actuated by the keys 44, which act by means of a guide member 45 on two levers 46 and 41, which are seated in the bearing 48 at 49 and 50. The lower lever 41 is provided with a rearwardly and upwardly directed leverarm 5|. A bell crank lever 52 is articulated to this lever arm 51 at ,53, the upper arm of the said bell crank lever fitting by means of a slot 54 over a pin '55 on the lever arm 5|, the lower arm 56 reaching under the spring loaded universal rail 51, which has a tendency to move the levers 46 and 41 and the key 44 into the rest position according to Figure 1." The upper extremity of the bell crank lever 52 is connected by means of a pull link 58 with the tail- 59 of the type bar 4|. A hook 60 is provided on the pulllink -58 to which the type bar return spring 6| is hooked, the other extremity of which is connected and acts upon a hook 62 o! the type lever.

In order to secure the key system in its end positions, the guide 45 is provided with a projection 63, adapted to lie against the upper lever 46, when the keys are in their rest positions. The projection 63 is so calculated, that the type bars remain still a, little above the rest seating 64, so that even the noise of the falling back of the type bar is ,very much reduced. If it is required, a noise damping insertion may be interpolated between the projection 63 and the lever 46, but this need only be thin, because, when the levers 46 stop, they and the projection 63 move in the same direction but at different speeds. As the very softly, so that very soft indeed.

The stopping of the key 44 and of the lever 41 in the lower position (Figure 6) may be-brought about by providing a projection 66 which may at its extremity be provided with an eccentric adjustable stop 65, said projection 66 being mounted on the guide member 45. When the keys 44 are in their depressed position (Figure 6) the stop 65 lies against the lever 41, so that any further depression of the keys 44 and any further movement 0! their levers 46 and 41 is prevented. If this position is reached, then a certain amount of energy is stored in the type lever or bar 4| which also expresses itself by endeavouring to allow the type bar 4| to fly further against the roller 43; this movement is possible because the pull bar or link can move the bell crank lever 52 with its slot 54 to the right in respect of the pins 55 mounted on the lever 41. During this movement, not only does the return spring 6| act in a braking manner by reason of an increased tension on the kinetic energy of the type bar I, but also on the spring of the universal rail 51. By means oi! adjusting the abutment 65 the moment of stopping the key lever system can be altered and consequently theaction. In such cases the two type reproduction on the into play upon said arrest length or .the travel, during which alone the kinetic energy of the type bar is active. It is therefore possible here also to adjust the degree or the. striking-energy accurately.

It is of course self-evident that individual organs or means of the actuating arrangement may be varied or altered, without thereby ex ceedlng the scope of the invention.

What I claim is:

1. In a typewriter having a platen, a pivoted key lever and a pivoted type lever; an independently pivoted intermediate lever connected to the key lever, an auxiliary lever connected at its respective ends to the intermediate and type levers,'said intermediate and auxiliarylevers and their connections shifting the type lever to a ready position upon a depression of the key lever, and combined lost motion and braking intermediate and auxiliary levers and a spring to resist lost motion between said levers. 2. In a typewriter having a platen, a pivoted key lever anda pivoted type lever; a pair of mutually connected levers, one of which is pivoted independently of the key lever but has a-connection therewith for swinging said pair of levers upondepression of the key lever, the other one of said pair of levers being connected to the type lever, means for arresting the motion of the key lever when the type lever is advanced to the ready position by said swinging of the pair of levers, and combined lost motion and braking means embodied in said pair of levers, coming of the key lever and enabling a shifting of one of said levers in respect to the other by the momentum of the type lever in advancing from said ready position to thetion between said pair of levers and a spring to resist lost motion between said levers.

3. In a typewriter having a platen, a pivoted keylever and a pivoted type lever; a pivoted intermediate lever connected at one end to the key lever, an auxiliary lever pivoted at one end to the intermediate lever and having a connection at its other end to the type lever for swinging the latter to a ready position upon depression of said key lever, means for arresting the motion of the key and intermediate levers when the type lever reaches said "ready position, andv combined lost motion and braking means embodied in said intermediate and auxiliary leversxenabling 10st motion or the auxiliary lever relative to the intermediate lever responsive to the momentum of the type lever in its movement from. the ready to its printing position against the platen, and producing a braking effect upon the type lever to diminish'its impact, said means including a pin and hole connection between the "intermediate and auxiliary levers and a spring to resist lost motion between said levers.

4. In a typewriter having a platen, a pivoted key lever and having a pin, an auxiliary lever connected to'the tyne lever and having an oversized hole containing the pin, means pivotally connecting the intermediate and auxiliary levers, said intermediate and auxiliary levers and their connections shifting the type lever to a "ready position upon a depression of the key lever, means for arresting the motion of the key and intermediate levers so that the momentum of the type lever in its subsequent flight to the printing position against the platen will displace the auxiliary lever in respect to the intermediate lever because of the loose connection afforded by the pin and oversized hole, and a spring carried by the intermediate lever, being in constant contact with a portion of the auxiliary lever but being flexed by said displacement of the auxiliary lever to brake the printing impact.

5. In a typewriter having a platen, a pivoted key lever and a pivoted type lever; an ihtermediate pivoted lever connected to the key lever and having a pin, an auxiliary lever connected to the type lever and having an oversized hole containing the pin to constitute a lost motion device, means pivoting the intermediate and auxiliary levers together, said intermediate and auxiliary levers shifting the type lever to a ready position upon a. depression of the key lever, means for arresting the motion of the key lever when said ready position is reached, a leaf spring, and two suspension points on the intermediate lever to which the respective ends of the spring are attached, said points being so located in refmamas erence to the pin as to maintain constant contact of the spring with a portion of the auxiliary lever, said'auxiliary lever being displaced on the intermediate lever because of their pin and hole connection by forceof the momentum of the type lever in its flight from the ready to the printing position against the platen, thereby to flex the spring and brake the printing impact.

6. In a typewriter having a platen, a rail, a pivoted key lever and a pivoted type lever; a pivoted intermediate lever, an auxiliary lever pivoted to the intermediate lever and connected to the type lever, a rocking lever having a rolling surface in contact with the rail, being connected at its ends to the key and intermediate levers, the rocking action of the rocking lever on the rail swinging the type lever from a resting to a ready position with increasing velocity upon a depression of the key lever, means to arrestthe depression of the key lever, means mutually embodied in the intermediate and auxiliary levers providing a lost motion device enabling 10st motion of the auxiliary lever relative to the intermediate lever as the type lever moves by momentum from said ready position to its printing position against the platen, and a spring carried by the intermediate lever being in constant engagement with said device to resist said lost motion and thereby diminish the momentum of the type lever.

HUGO BENZING. 

